This invention relates to a medical device and more particularly to an improved vena puncture (or medical) device and method for drawing blood.
As is customary in many medical procedures, a substantial number of blood samples of about five (5) to ten (10) cubic centimeters are drawn from the patient to provide a specimen or specimens for a variety of tests. These tests can indicate a method of treatment, a type of illness and provide other useful information about the health of the person. A primary method of drawing blood is to insert a needle in the arm. The blood is then withdrawn through the needle and used in the various testing procedures.
In order to avoid multiple probings required by a number of different samples of blood for different tests, a vena puncture device is known medical instrument. A standard vena puncture device includes a hollow, cylindrical needle having a sharpened point for puncturing and an opening at both ends mounted in a tubular member. One end of needle is outside the tube and serves to puncture the vein. At the other end of the needle, which is inside the tube, a sealed vacuum tube is applied such that the needle within the vena puncture tube punctures the vacuum seal of the vacuum tube. The vacuum then draws blood into the vacuum tube.
This vena puncture device reduces the number of punctures that must be made in the vein to one for the purpose of drawing blood. Only one puncture is made. As many vacuum tubes as required are used for samples. Still there is a problem. The insertion and removal of the vacuum tube does cause a great deal of pain and discomfort to the patient. The pain and discomfort are such that some people even put off getting necessary medical assistance.
Other problems with the vena puncture device involve the friction between the vacuum tube and the vena puncture device at the removal of the vacuum tube therefrom. If the vena puncture device is held too loosely while the vacuum tube is removed, the device might be removed from the vein. Such premature removal of the device from the vein requires a second puncture and abrogates the advantages of the device. If the vena puncture device is held too tightly while the vacuum tube is removed, the device might pass right through the vein. Such an injury is painful and undesirable.
Friction between the vacuum tube and vena puncture device can also be a problem. The device must be small enough to guide the tube, while avoiding friction which causes pressure and pain. Avoidance of friction can create a size too large to provide guidance of the vacuum tube. Guidance for the vacuum tube can create a size for the vena puncture device too small to avoid friction.
An apparatus designed to solve these problems must be simple to operate and not increase the bulk of the vena puncture device in any substantial fashion. If a method and an apparatus can be developed which minimizes this pain by simplifying the insertion or withdrawal of the vacuum tube without unduly increasing the size or the difficulty of operation, great advantages in reduction of pain and increase in the comfort of the patient are obtained.